class_docstr: 重载 StreamHandler 使得替换 sys.stdout 的时候能够生效。
docstr: Flushes the stream.
docstr_tok: ["Flushes","the","stream","."]
code: def flush(self):
      """
      Flushes the stream.
      """
      self.acquire()
      try:
          sys.stdout.flush()
      finally:
          self.release()
  
file_path: fastNLP/fastNLP/core/log/handler.py
imports: import logging
  import sys
  from logging import getLevelName
label_desc: Use image node_id 2 for calling the StdoutStreamHandler obj's underlying member method code with example usage: obj.flush() without return types